LI-COR LI-7815, Instruction Manual

Page: 32 / 98

Section 3. Applications of the LI-7815
Connecting the air inlet and outlet
Air is drawn into the sample cell through the air inlet. Connect a ¼" outside dia-
meter metal or plastic tube to the air inlet compression fitting. The nut and ferrule
sets are in the accessories kit.
Caution: Be very careful when working near standing water. If water is drawn
into the air inlet, the instrument will have to be repaired at the factory.
Figure 3-2. When connecting a tube to the air inlet, use steel ferrules to form a good seal.
Tighten the nut over the ferrule set until it is finger tight. For metal and plastic
tubing, tighten it an additional 1¼ turns if you are connecting the tube for the first
time. For plastic tube that is highly pliable, insert a stainless steel tube insert (300-
18126) to make the end of the tube rigid. When reconnecting a plastic or metal tube
that has been connected previously, simply tighten it ¼ turn beyond finger tight.
Tubing can be connected to the outlet in the same way.
Important: Abrupt pressure transients up to 35 kPa above or below ambient pres-
sure may cause momentary status warnings, inlet plugged warnings, and meas-
urement inaccuracies. Longer lasting pressure excursions or larger pressure
transients may cause the instrument to reinitialize measurement control loops.
3-2 LI-7815 CO₂/H₂O Gas Analyzer